Field of the Industrial Application
The present invention relates to an electrically actuated date-stamping apparatus.
A type of date-stamping system is known from Japanese Patent Disclosure No. 58-211289 which includes an electric motor energized by clock signals at regular time intervals to perform the forward movement of printing belts automatically. In this system, printing belts are driven by an electric motor energized by a clock signals. If each of the printing belts has a smooth backface, it is difficult to make a positive advancement of that printing belts since there is slippage between the smooth backface of the printing belt and the surface of the corresponding pulley. In order to overcome this problem, a proposal is made in the above Patent Disclosure to roughened the backface of each printing belt. However, the roughened backface raises another problem in that an irregularity of density is created in the stamped characters and the characters are deformed.
A system in which printing characters are formed on the peripheral face of a disc formed with a gear wheel at the side of the disc is known from by Japanese Utility Model Disclosure No. 61-180751 and Japanese Patent Disclosure No. 85-233877. Although such a disc-type structure can positively overcome the aforementioned problem, each of the printing discs will necessarily have an increased external diameter when numerals corresponding to the days in one month are formed on the peripheral face of the disc. This will increase the overall size of the date-stamping device, and make it inconvenient to handle.
It is therefore an object of the present invention to provide a date-stamping apparatus in which no slippage results between each of belt-driving wheels and a corresponding endless printing belt.
It is a further an object of the present invention to provide a date-stamping apparatus which avoids any irregularity of density of the stamped characters and any deformation of the stamped characters, even if the character portion of the stamping belt is made from soft, cellular rubber to absorb ink.
It is another object of the present invention to provide a date-stamping apparatus in which, even if an endless printing belt is larger than the conventional belt, whole belt assembly can be easily housed in a compact casing.